Methods and apparatus for electrical microcurrent stimulation therapy

ABSTRACT

A method and apparatus for providing microcurrent stimulation therapy to a body part is disclosed. In one embodiment, a method allows digital control of the modulation frequency of the microcurrent signal. The method includes receiving a first digital data word which is used to produce a first frequency related to the first digital data word, whereupon, a first microcurrent signal at the first frequency is applied to the body part. A second digital data word is received and used to produce a second frequency related to the second digital data word. A second microcurrent signal at the second frequency is applied to the body part. In another embodiment, a method allows direct digital synthesis of the microcurrent stimulation signal. A first digital data word is used to produce a first analog voltage which is applied to the body part. A second digital data word is used to produce a second analog voltage which is also applied to the body part, where the first analog voltage is different from the second analog voltage. In yet another embodiment, an apparatus for providing microcurrent stimulation therapy includes a digital-to-analog converter, a controller and a plurality of data words. The controller is coupled to the digital-to-analog converter and supplies the digital-to-analog converter with digital data words in order to generate an electrical signal for the microcurrent stimulation therapy.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation-in-part of and claims the benefit ofU.S. patent application Ser. No. 09/114,815, filed Jul. 13, 1998, nowU.S. Pat. No. 6,035,236, the disclosure of which is incorporated byreference.

BACKGROUND OF THE INVENTION

The present invention relates generally to methods and apparatus forelectrical microcurrent stimulation therapy, and more particularly tomethods and apparatus for providing electrical microcurrent stimulationaround an eye to combat visual system diseases, such as maculardegeneration.

Chronic pain is a problem for millions of individuals throughout theworld. One method of treating such pain is to provide microcurrentstimulation around or near the areas where the pain is occurring.Microcurrent, which typically is defined as current below 1 milliamp,can provide rapid and long-lasting pain relief for a wide variety ofpain syndromes. Generally, microcurrent stimulation therapy typicallycomprises applying a current in the range of about 20 to about 300microamps to the affected area. The current or microcurrent blocksneuronal transmission of pain signals and stimulates the release ofendorphins to help relieve the pain in chronic and acute pain patients.

While the current level can be an important factor in microcurrentstimulation therapy, frequency modulation and the waveform of theelectrical signal are also important. Some electrical stimulationtherapy devices currently known in the art typically allow the user tomanually adjust the frequency ranges and types of waveform signalsapplied to the patient. For example, the MicroStim 400 device,manufactured by MicroStim, Inc., located in Tamarac, Fla., features acombination of a carrier waveform having a modulated frequency thereon.The MicroStim device is covered by U.S. Pat. No. 4,989,605, issued onFeb. 5, 1991 to Joel Rossen and entitled “Transcutaueous ElectricalNerve Stimulation (TENS) Device”, the contents of which is incorporatedherein by reference. The theory behind the MicroStim 400 device is thatthe carrier wave is designed to take the modulated frequency deep intothe body for consistent and rapid pain relief. However, a disadvantageof the MicroStim 400 device is that the signal that it generatesproduces most of its power at individual frequencies 105. That is, whenviewing the signal produced by the MicroStim 400 in the frequencydomain, the majority of the power output from the signal resides atdiscrete frequencies. Accordingly, the therapeutic effect of the signalmay not be maximized.

Another device which can be used for microcurrent stimulation therapy isthe Amrex Z-Stim device manufactured by Amrex, Corp. of Carson, Calif.The Z-Stim device is a multi-signal interferential stimulator thatprovides multiple swept frequency sinusoidal signals. The applicationsfor sinusoidal signals are more appropriate for muscle stimulation andaddressing problems associated with pain, edema and rehabilitation forcertain neuromuscular and orthopedic problems.

In addition to chronic pain relief, microcurrent therapy is being usedto treat a number of visual system diseases, including maculardegeneration and retinitis pigmentosa.

Age-related macular degeneration (AMD) is the leading cause of legalblindness in the United States in persons over 65 years old. Accordingto a March 1997 Review of Optometry Journal, 10% of our population overage 52 has AMD and 33% of individuals over age 75 have AMD. It isestimated that more than 13 million Americans now have AMD and that, bythe time the Baby Boomers reach age 65, there will be over 30 millioncases of AMD, almost 25% of our population over 65.

Normal retinal cell function is a photochemical reaction convertinglight energy to an electrical impulse which travels to the brain andvision occurs. With AMD and other visual system diseases, diseased,inflamed retinal cells eventually lose cell function. Adenosinetriphosphate (ATP) levels drop, protein synthesis drops, the electricalresistance goes up, and cell membrane electrical potential goes down.Basically, the cells seem to go dormant for a time before they die. Itis believed that, if electrical stimulation is provided to the cellsbefore they die, blood vessel permeability is increased, a more normalcellular electrical potential will be achieved, the ATP levels willincrease, protein synthesis will occur again, and normal cell metabolismwill be restored. In addition, electrical stimulation appears to have ahealing effect on the small blood vessels in the retina, promoting amore efficient delivery of nutrients to the retinal cells and a moreefficient uptake of proteins that can accumulate on the retina. Thus, itis believed that microcurrent stimulation will help rejuvenate the cellsin the retina to slow or stop degeneration of the eye due to AMD. Withthe proper microcurrent stimulation waveform and therapy procedures, AMDmay be slowed or stopped in a large number of people suffering from thedisease.

While microcurrent stimulation therapy has been used to treat AMD andother visual system diseases, the methods and apparatus used in theprior art do not appear to maximize the therapeutic effect. For example,as mentioned briefly above, the devices for providing microcurrentstimulation therapy are limited in the types of waveforms and frequencyranges which they may provide for therapy.

SUMMARY OF THE INVENTION

Accordingly, it is an advantage of the present invention to providenovel methods and apparatus for providing microcurrent stimulationtherapy to a body part to combat chronic pain, injury, or disease inthat body part.

Another advantage of the present invention is to provide methods andapparatus for treating various diseases, including macular degenerationand retinitis pigmentosa.

Yet another advantage of the present invention is to provide anapparatus which generates unique waveforms that can be used formicrocurrent stimulation therapy. The unique waveforms produce aspectral response desired for treating the disease of interest.

Still another advantage of the present invention is to provide anapparatus which can produces unique waveforms under digital control byusing either digitally controlled frequency modulation or direct digitalsynthesis. Digital control can provide more precision and versatility inthe control of the spectral output for microcurrent therapy.

The above and other advantages of the present invention are carried outin one embodiment by an apparatus for supplying an electrical signal toa body part in order to provide microcurrent stimulation therapy to thebody part. In this embodiment, the apparatus includes adigital-to-analog converter, a controller and a plurality of data words.The controller is coupled to the digital-to-analog converter andsupplies the digital-to-analog converter with digital data words inorder to generate an electrical signal to a voltage controlledoscillator which serves as the basic source for the microcurrentstimulation therapy.

In another embodiment, a method allows digital control of the modulationfrequency of the microcurrent signal preferably using a look-up table.The method includes receiving a first digital data word which is used toproduce a first frequency related to the first digital data word,whereupon, a first microcurrent signal at the first frequency is appliedto the body part. A second digital data word is received and used toproduce a second frequency related to the second digital data word. Asecond microcurrent signal at the second frequency is applied to thebody part.

In yet another embodiment, a method allows direct digital synthesis ofthe microcurrent stimulation signal. A first digital data word is usedto produce a first analog voltage which is applied to the body part. Asecond digital data word is used to produce a second analog voltagewhich is also applied to the body part, where the first analog voltageis different from the second analog voltage.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention may be derived byreferring to the detailed description and claims when considered inconnection with the figures, wherein like reference numbers refer tosimilar items throughout the figures, and:

FIG. 1 is a diagram of a microcurrent stimulation therapy apparatushaving a microcurrent signal generator and a probe for applying themicrocurrent to a body part;

FIG. 2 is a block diagram of a circuit embodying the microcurrent signalgenerator of FIG. 1;

FIG. 3 is a detailed circuit diagram of one embodiment of themicrocurrent signal generator circuit of FIG. 2;

FIG. 4a illustrates eight therapy points around an eyelid to whichmicrocurrent stimulation therapy may be applied in accordance with amethod for treating visual system diseases;

FIG. 4b illustrates eight therapy points on the back of the neck towhich microcurrent stimulation therapy may be applied in accordance witha method for treating visual system diseases;

FIG. 4c illustrates ten therapy points on the ear to which microcurrentstimulation therapy may be applied in accordance with a method fortreating visual system diseases;

FIG. 4d illustrates four therapy points on an arm to which microcurrentstimulation therapy may be applied in accordance with a method fortreating visual system diseases;

FIG. 5a illustrates a periodic sinusoidal wave signal having a setfrequency which is a waveform signal generated by a prior artmicrocurrent generator;

FIG. 5b illustrates the spectral or frequency response of the sinusoidalwave signal of FIG. 5a;

FIG. 6a illustrates a periodic square wave having a set frequency whichis a waveform signal generated by a prior art microcurrent generator;

FIG. 6b illustrates the spectral or frequency response of the squarewave signal of FIG. 6a;

FIG. 7a is a swept sinusoidal waveform signal varying from about 0 Hz toabout 125 Hz over a time frame in excess of 100 microseconds;

FIG. 7b is the spectral or frequency response of the waveform signal ofFIG. 7a;

FIG. 8a is a swept sinusoidal waveform varying from about 0 Hz to about1.1 MHz over a time frame in excess of 1 microseconds;

FIG. 8b is the spectral or frequency response of the waveform signal ofFIG. 8a;

FIG. 9 is an embodiment which allows digital control of the modulationfrequency;

FIG. 10 is an embodiment which produces the output waveform using directdigital synthesis;

FIG. 11 is an embodiment of a triangular waveform;

FIG. 12 is an embodiment of a ramp waveform;

FIG. 13A is a first embodiment of bi-phasic pulses; and

FIG. 13B is a second embodiment of bi-phasic pulses.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

The present invention comprises methods and apparatus for providingmicrocurrent simulation therapy for the treatment of chronic pain,visual system diseases and other bodily defects or diseases. Moreparticularly, the present invention relates to a microcurrent waveformgenerator which generates sweep wave signals for use in microcurrentstimulation therapy. As discussed in more detail below, the microcurrentsweep wave generator disclosed herein may be used for any type ofmicrocurrent stimulation therapy and will find its greatest use intreating patients suffering from macular degeneration.

In addition, the present invention relates to a novel method fortreating visual system diseases such as macular degeneration andretinitis pigmentosa using microcurrent stimulation therapy techniques.

With reference to FIG. 1, a novel microcurrent stimulation therapyapparatus 10 is shown in accordance with the present invention. Therapyapparatus 10 preferably comprises a sweep wave signal generator 12, astimulation probe 14, and an electrode 16. Preferably, stimulation probe14 is connected to sweep wave signal generator 12 via a first electricalconnector 18, and electrode 16 is connected to sweep wave signalgenerator 12 via a second electrical connector 20. As illustrated inFIG. 1, a probe tip 22 preferably is connected to the end of stimulationprobe 14 opposite the end of probe 14 connected to first electricalconnector 18.

Stimulation probe 14 preferably comprises a shielded hand-held probeconfigured to administer microcurrent stimulation to various points onone or more body parts. In accordance with a preferred embodiment of thepresent invention, probe tip 22 preferably comprises a cotton swabmoistened or dampened with a conductive gel. The dampened cotton swaballows for the gentle administration of the microcurrent to the bodypart without undue discomfort. However, while one embodiment of thepresent invention illustrates a probe tip 22 as being a cotton swab, oneskilled in the art will appreciate that other types of probe tips may beused. For example, probe tip 22 may be made from a variety of differentmetals like copper, brass, aluminum, or the like, or probe tip 22 may bemade from metal combinations or other conductive materials. In anyevent, any suitable probe tip may be used and, thus, the presentinvention is not limited to the illustrated embodiment.

In accordance with a preferred embodiment of the present invention,electrode 16 preferably comprises a handheld brass electrode. As oneskilled in the art will appreciate, when a patient receivingmicrocurrent stimulation therapy holds electrode 16, a closed circuit iscreated with stimulation probe 18. That is, by holding electrode 16,current from probe 18 will travel through the body, to brass electrode16 and back to sweep wave signal generator 12.

While the illustrated embodiment shows a handheld brass electrode 16,any electrode configuration may be used. For example, electrode 16 maybe a conductive clip device which attaches to a body part such as afinger, ear, arm or the like.

As discussed briefly above, first electrical connector 18 is configuredto connect stimulation probe 14 to sweep wave signal generator 12, andsecond electrical connector 20 is configured to connect electrode 16 tosweep wave signal generator 12. In the illustrated embodiment, first andsecond electrical connectors 18 and 20 each preferably include a firstconnector end 24 for connection to generator 12 and a second connectorend 26 for connection to stimulation probe 14 and electrode 16,respectively. In accordance with this aspect of the invention,connectors 18 and 20 are removable from generator 12 and probe 14 andelectrode 16.

In accordance with an alternative embodiment of the present invention,connectors 18 and 20 may be hardwired to generator 12, or to probe 14and electrode 16, or to both generator 12 and probe 14 and electrode 16.In addition, in accordance with yet another alternative embodiment ofthe present invention, electrical connectors 18 and 20 may comprise anysuitable electrical connection device currently known in the art orhereinafter developed.

Still referring to FIG. 1, a more detailed description of sweep wavesignal generator 12 will now be discussed. As discussed in detail below,sweep wave signal generator 12 preferably is configured to generate oneor more sweep wave signals having various waveform, sweep frequency,sweep time, duty cycle, center frequency, frequency window, andamplitude characteristics. In accordance with a preferred embodiment ofthe invention, the generated sweep wave signal(s) are frequency variedsignals. That is, the frequency of the signals vary over time.

To generate the different sweep wave signals, sweep wave signalgenerator 12 may produce a single sweep wave signal, or alternatively,sweep wave signal generator 12 may generate a composite signalcomprising two independent swept wave signals or a swept wave signal anda non-swept wave signal. In accordance with this aspect of the presentinvention, sweep wave signal generator 12 preferably comprises a firstwaveform control 32 and a second waveform control 34. First waveformcontrol 32 preferably controls the waveform type of a first sweep wavesignal, and second waveform control 34 preferably controls the waveformtype of a second sweep wave signal. First and second waveform controls32 and 34 may be adjusted to produce a variety of different sweepwaveforms. For example, by adjusting first and second controls 32 and34, generator 12 will produce different waveforms, including sinusoidalwaveforms, ramp waveforms, triangular waveforms, rectangular or squarewaveforms, step waveforms, window waveforms, unipolar waveforms, bipolaror bi-phasic waveforms or steady-state DC signals, to name a few. Bycombining different waveform types having different sweep frequenciesand sweep times, a large variety of therapeutic sweep waves may begenerated.

In addition to controlling the type of waveforms generated, sweep wavesignal generator 12 preferably is configured to control the range offrequencies between which the selected waveforms sweep, as well as thesweep time for performing the sweep of frequency ranges. In accordancewith this aspect of the invention, generator 12 preferably has a firstlow frequency control 36, a first high frequency control 38, a firstsweep time control 39, a second low frequency control 40, a second highfrequency control 42, and a second sweep time control 43. First lowfrequency control 36 preferably controls the low frequency threshold forthe first sweep wave signal, first high frequency control 38 controlsthe high frequency threshold of the first sweep wave signal, and firstsweep time control 39 controls the sweep time of the first sweep wavesignal. Similarly, second low frequency control 40 preferably controlsthe low frequency threshold of the second sweep wave signal, second highfrequency control 42 controls the high frequency threshold of the secondsweep wave signal, and second sweep time control 43 controls the sweeptime of the second sweep wave signal.

In accordance with a preferred embodiment of the present invention, thelow frequency thresholds for both sweep wave signals may be in the rangeof about 0 Hz to about 400 Hz. Similarly, the high frequency thresholdfor the two sweep wave signals may be in the range of about 0 Hz toabout 2000 Hz. The sweep time for both the first and the second sweepwave signals preferably is in the range of about 7 seconds to about 60seconds, and more preferably about 15 seconds. While the illustratedembodiment shows a low frequency control and a high frequency controlfor each sweep wave signal, one skilled in the art will appreciate thatany frequency control scheme may be used. For example, each sweep wavesignal may have only one frequency control, or one low and one highfrequency control may control both sweep wave signals. In any event, thepresent invention is not limited to the illustrated embodiment.

Still referring to FIG. 1, sweep wave signal generator 12 preferablyfurther comprises a voltage signal control 44, a current control 46, afirst signal monitor port 50, a second signal monitor port 52, and adata-acquisition system port 54.

As discussed in more detail below with reference to FIGS. 2 and 3, sweepwave signal generator 12 preferably further comprises a voltage limitingcircuit and a current limiting circuit. In accordance with this aspectof the invention, voltage control 44 is configured to control themagnitude of the voltage signal peak or peak-to-peak output. Similarly,current control 46 preferably is configured to control the currentsupplied to the body part of the patient by controlling the currentlimiting circuit.

As discussed in greater detail below, sweep wave signal generator 12 maybe connected to one or more oscilloscopes, spectrum analyzers orwaveform displays via first and second signal monitor ports 50 and 52.By connecting generator 12 to one or more oscilloscopes, spectrumanalyzers, or waveform displays, the waveform signal and current levelat various locations within the generator circuit can be monitored. Inaddition, sweep wave signal generator 12 may further include adata-acquisition port 54 for connecting generator 12 to adata-acquisition system and/or a strip chart recorder. In accordancewith this aspect of the present invention, generator 12 preferably isconfigured to record various data, such as waveform, current and voltagelevels, and the like for different patients, and then download the datato a data-acquisition system for monitoring and analysis. In thismanner, a doctor or practitioner can analyze data concerning variationsin current levels between patients and different diseases of the visualsystem, as well as variations in the swept waveform for differentpatients and disease states. The doctor or practitioner can then usethis data to track therapy progress, develop better therapy proceduresfor different patients, and monitor variabilities in treatment points.In addition, the doctor or practitioner can monitor probe contactconsistency and patient progress for self-administered therapy patients.That is, for patients who use or administer the micro-currentstimulation therapy to themselves, at home, the doctor or practitionercan use the collected data to determine whether the patient isadministering the therapy correctly and whether the therapy protocolneeds to be adjusted for that particular patient.

As one skilled in the art will appreciate, sweep wave signal generator12 may include both voltage control 44 and current control 46, orgenerator 12 may be configured with only one of the two controls. Forexample, by controlling the magnitude of the voltage output signal for agiven patient impedance, the current supplied to the patient is alsocontrolled. Similarly, by controlling the current supplied to a patienthaving a given impedance, the voltage is also controlled. Thus, thepresent invention is not limited to the illustrated embodiment. Inaddition, while the illustrated embodiment of sweep wave signalgenerator 12 shows a number of different control features, one skilledin the art will appreciate that certain control features may beeliminated and other control features may be added without departingfrom the spirit of the invention. For example, while not illustrated inthe figures, sweep wave signal generator 12 may further comprise dutycycle controls for controlling the duty cycles of the first and secondsweep wave signals.

Finally, sweep wave signal generator 12 preferably further comprises acurrent level indicator 48, a first frequency indicator 49-1, and asecond frequency indicator 49-2. In accordance with this aspect of theinvention, current level indicator 48 preferably displays the currentbeing supplied to the patient. Current level indicator 48 may beconfigured to display root-mean-square (rms) or average current outputfor certain segments of treatment time.

In addition, in accordance with one embodiment of the present invention,first and second frequency indicators 49-1 and 49-2 preferably areconfigured to display the frequency of the first and second sweep wavesignals, respectively, as the signal sweeps through the frequencyranges. Alternatively, in accordance with another embodiment of thepresent invention, first and second frequency indicators 49-1 and 49-2may be configured to display the frequency ranges between which thefirst and second sweep waves are to sweep.

Referring now to FIG. 2, a block circuit diagram of one embodiment of asweep wave signal generator circuit 55 is illustrated. In accordancewith a preferred embodiment of the present invention, sweep wave signalgenerator circuit 55 preferably comprises a first sweep signal generator60, and a second sweep signal generator 62. Both first and second sweepwave signal generators 60, 62 preferably comprise a sweep controlcircuit 64 and a signal generator 66. Sweep control circuit 64preferably controls the sweep frequencies, sweep times and duty cyclesof the signals, and signal generator 66 preferably generates aparticular waveform having the sweep frequencies, sweep times and dutycycles dictated by control circuit 64. First and second sweep wavesignal generators 60 and 62 may be configured to generate swept waves,or non-swept waves. For example, by setting the high and low sweepfrequencies to the same frequency for a particular signal, the signalgenerator will generate a signal having a set frequency.

As one skilled in the art will appreciate, first and second sweep signalgenerators 60 and 62 may comprise any suitable sweep signal generatorcurrently known in the art. For example, function generator with sweepcontrol, product no. PM5132, manufactured by Philips Corporation, may beused. As discussed briefly above, sweep signal generator 60 and 62 maybe configured to generate a wide variety of waveforms having a variablerange of sweep frequencies and sweep times.

In accordance with the embodiment illustrated in FIG. 2, first sweepsignal generator 60 preferably generates a first sweep wave signal 68and second sweep signal generator 62 preferably generates a second sweepwave signal 70. A signal combiner/adder circuit 72 preferably receivesfirst sweep wave signal 68 and second sweep wave signal 70 and combinesthe two signals into a single sweep wave signal 74. From combiner/addercircuit 72, sweep wave signal 74 preferable passes to a buffer/amplifiercircuit 76, which is configured to amplify and buffer single sweep wave74, generating a buffered sweep wave signal 78.

In accordance with one embodiment of the present invention, bufferedsweep wave signal 78 preferably passes into a voltage clipping orlimiting circuit 80, which is configured to control the polarity of theoutput voltage to a predetermined voltage level and polarity. The outputof clipping or limiting circuit 80 is a clipped voltage signal 82 whichpreferably passes to a current limiting circuit 84 configured to limitthe total current output supplied to a particular body part. Connectedto current limiting, circuit 84 is a current level indicator 86, whichpreferably is a volt meter configured to monitor and display the outputcurrent level.

As mentioned briefly above, sweep wave signal generator 12 preferablycomprises a voltage control 44 and a current control 46. In accordancewith this aspect of the invention, voltage control 44 preferably isconfigured to control the voltage signal peak or peak-to-peak outputfrom voltage clipping or limiting circuit 80. For example, by adjustingvoltage signal control 44, voltage clipping or limiting circuit 80 isadjusted so that the amplitude of the output voltage changes asnecessary. Similarly, current control 46 of signal generator 12preferably is configured to control the current output from currentlimiting circuit 84.

Current level indicator 86 may comprise any suitable current measuringand displaying device. As discussed in more detail below with referenceto FIG. 3, current level indicator 86 may comprise, for example, avoltage measuring device configured across current limiting circuit 84.As one skilled in the art will appreciate, the amount of current flowingthrough current limiting circuit 84 is a function of the voltage acrossthe circuit, as well as the resistance of the circuit itself. Once thecurrent level is determined, current level indicator 86 preferablydisplays the current level on current level display 48 of signalgenerator 12 (see FIG. 1). Current level indicator 86 can be configuredto measure the root-mean-square (RMS) current, or indicator 86 may beconfigured to measure an average current over a particular time period.

In accordance with another preferred embodiment of the presentinvention, signal generator circuit 55 may be configured without voltageclipping or limiting circuit 80. In accordance with this preferredembodiment of the invention, amplified sweep wave signal 78 passesdirectly to current limiting circuit 84. This particular embodiment ofthe invention is illustrated in FIG. 2 as dotted line 78 passing intocircuit 88 comprising current limiting circuit 84 and current levelindicator 86. In accordance with this second embodiment of the presentinvention, current limiting circuit 84 and current level indicator 86preferably operate in the same general manner as that described abovewith reference to the first embodiment. Accordingly, a detaileddiscussion of circuit 88 will not be discussed further.

In accordance with yet another embodiment of the present invention,sweep wave signal generating circuit 55 may further comprise connections90 and 92 for connection to one or more oscilloscopes, spectrumanalyzers or waveform displays. As illustrated in FIG. 2, in accordancewith a preferred embodiment of the present invention, signal generatingcircuit 55 preferably has two connections, one prior to voltage clippingor limiting circuit 80 and one after voltage clipping or limitingcircuit 80. In accordance with this aspect of the invention, anoscilloscope, spectrum analyzer, or waveform display connected toconnection 90 will display the waveform of the sweep wave signal frombuffer/amplifier circuit 76, and the second oscilloscope, spectrumanalyzer, or waveform display connected to connection 92 will displaythe sweep wave signal after it has passed through voltage clipping orlimiting circuit 80. Accordingly, the operator of the device can be surethat voltage clipping or limiting circuit is functioning properly byanalyzing the signals entering and leaving the circuit. In theembodiment in which the voltage clipping or limiting circuit iseliminated, only one connection to an oscilloscope or spectrum analyzeris present.

In addition, as mentioned briefly above, the sweep wave signal generatorcircuit 55 may further comprise a data acquisition module 94 forcollecting data about the performance of the therapy device, and inparticular, generator circuit 55. For example, in accordance with theillustrated embodiment, data acquisition module 94 preferably isconnected so that it can monitor first and second sweep waves 68 and 70,buffered sweep wave signal 78, clipped voltage signal 82, and thecurrent and voltage of the output signals. In accordance with thisaspect of the invention, the collected data can then be downloaded todata acquisition system for analysis by a doctor or therapist. As oneskilled in the art will appreciate, the data acquisition system maycomprise any suitable data acquisition system, such as a computer systemconfigured to manipulate and display such data.

Referring now to FIG. 3, a detailed circuit diagram of one embodiment ofsweep wave signal generating circuit 55 is illustrated. In accordancewith the illustrated embodiment in FIG. 3, signal generating circuit 55preferably comprises a first sweep wave signal generator 60, a secondsweep wave signal generator 62, a signal combiner or adder circuit 72 abuffer/amplifier circuit 76, a voltage limiting or clipping circuit 80,a current limiting circuit 84 and a current level monitor/indicator 86.

In accordance with this particular embodiment of the present invention,signal adder or combiner circuit 72 and buffer/amplifier circuit 76preferably are combined into a single operational amplifier circuit 100.Op amp circuit 100 preferably receives a first sweep wave signal 102from first sweep wave signal generator 60 and a second sweep wave signal104 from second sweep wave signal generator 62. In accordance with thisaspect of the invention, first sweep wave signal 102 is connected tonegative input terminal 112 of an op amp 110 through a first resistor106, and second sweep wave signal 104 is connected to negative inputterminal 112 of op amp 110 through a second resistor 108. First resistor106 and second resistor 108 preferably are in the range of about 1kiloohm to about 25 kiloohms, and more preferably are about 10 kiloohms.

Op amp 110 further comprises a positive input terminal 114 whichpreferably is connected to ground, and an output terminal 116 whichpreferably is connected in a negative feedback loop to negative inputterminal 112 through a variable resistor 118. In accordance with apreferred embodiment of the present invention, variable resistor 118 mayhave a variable resistance which ranges between about 1 to about 50kiloohms, and more preferably ranges between about 3.3 to about 7.8kiloohms.

While one embodiment of the present invention disclosed herein utilizesan op amp as a signal adder and buffer amplifier, one skilled in the artwill appreciate that other circuit configurations may be used toaccomplish the amplifier, adder, and buffering tasks. Thus, the presentinvention is not limited to an embodiment comprising an op amp circuit.

From operational amplifier circuit 100, a single sweep wave signal 120passes into voltage clipping or limiting circuit 80. In accordance withthis aspect of the invention, voltage clipping or limiting circuit 80preferably comprises a diode 22 and a variable resistor 124. Variableresistor 124 is connected between a first terminal of diode 122 andground. With this particular configuration, the adjustment of variableresistor 124 preferably adjusts the limit of the voltage amplitudeoutput. In accordance with a preferred embodiment of the invention,variable resistor 124 preferably has a resistance which ranges betweenabout 5 to about 50 kiloohms, and more preferably between about 15 toabout 25 kiloohms.

While the illustrated embodiment of the present invention shows voltageclipping or limiting circuit 80 comprising a resistor/diode combination,one skilled in the art will appreciate that any voltage limiting circuitconfiguration may be used. For example, instead of a diode/resistorcombination, voltage clipping or limiting circuit 80 may comprise anoperational amplifier configured as a limiting circuit. Therefore, thepresent invention is not limited to the illustrated embodiment.

From voltage limiting circuit 80, a clipped wave signal 126 preferablypasses into current limiting circuit 84. In accordance with theillustrated embodiment of the invention, current limiting circuit 84comprises a resistor 128. As one skilled in the art will appreciate,since current equals the voltage divided by the resistance (I=V/R), thehigher the value of the resistor 128, the lower the current output. Inaccordance with the preferred embodiment of the invention, resistor 128preferably has a value between about 10 and about 500 kiloohms, and morepreferably a value between about 20 kiloohms and about 115 kiloohms.

While the illustrated embodiment shows resistor 128 as a constantresistance value, one skilled in the art will appreciate that to have acontrollable or variable current output, it may be desirable to replaceconstant resistor 128 with a variable resistor. In addition, whilecurrent limiting circuit 84 is shown as a resistor, any suitable currentlimiting circuit configuration may be used. For example, a circuitcomprising transistors, resistors, diodes, and the like may be usedinstead of a simple resistor.

As discussed above, current level monitor/indicator 86 is configured tomeasure the current output from current limiting circuit 84. In theillustrated embodiment, current level monitor/indicator 86 preferablycomprises a device which is configured to measure the voltage acrossresistor 128, which in turn will give the current flowing through theresistor. However, other current monitoring devices or circuits may beused. In addition, as discussed above with reference to FIG. 2, circuit55 may further comprise a data acquisition module for collecting therapyand waveform data.

The fundamental difference between the swept and the non-swept waveformis the continuous nature of the spectral characteristics and thetime-frequency variation with analog waveforms, and the almostcontinuous nature (i.e., somewhat discrete) for the spectralcharacteristics of a swept digital or pulsed waveform. There appears tobe some evidence that the human body behaves like a dispersive filterand a waveform that is swept in the appropriate manner may be preferredfor electro-therapy. Also, since the physiology and body chemistry foreach patient varies, the swept waveform is more likely to provide theoptimal frequency which maximizes the therapeutic value for largenumbers of people afflicted with various types of visual systemdiseases.

Referring now to FIGS. 5a, 5 b, 6 a, 6 b, 7 a, 7 b, 8 a, and 8 b,fundamental differences between discreet frequency wave signals andsweep wave signals is illustrated. Specifically, FIG. 5a illustrates a 2volt (peak-to-peak) sinusoidal waveform having a set frequency of about3 MHz. This type of waveform is a typical analog waveform generated bymicrocurrent stimulation devices currently known in the art. Asillustrated in FIG. 5b, the spectral or frequency components of thesinusoidal waveform appear at only one discreet frequency. With thistype of signal, all of the power from the signal is located at or nearthe 3 MHz frequency.

FIG. 6a illustrates a 3.2 volt (peak-to-peak) rectangular waveformhaving a peak overshoot and a frequency of about 6 MHz. Again, thiswaveform type is a typical digital or pulsed waveform produced bymicrocurrent stimulation devices currently known in the art. Asillustrated in FIG. 6b, the rectangular waveform has a fundamentalfrequency component at 6 MHz and diminishing harmonics at 18, 30 and 42MHz, respectively. With this type of signal, approximately 80% of thepower is associated with the fundamental frequency of 6 MHz.

Referring now to FIG. 7a, a 10 volt (peak-to-peak) swept sinusoidalwaveform varying from about 0 Hz to about 125 Hz over a time frame ofmore than 100 microseconds is shown. As illustrated in FIG. 7a, thefrequency of the waveform changes with time. FIG. 7b shows the frequencyor spectral characteristics of the waveform of FIG. 7a. Specifically, asillustrated FIG. 7b, the frequency or spectral characteristics of theswept analog waveform are continuous, not discreet, like they are withthe fixed frequency signal of FIGS. 5b. Thus, the power is notconcentrated at one or a few frequencies, but is spread over the entirefrequency range. The power at any discreet frequency in the spectrum is0 watts.

Finally, FIG. 8a illustrates a 10 volt (peak-to-peak) swept sinusoidalwaveform varying from 0 Hz to 1.1 MHz over a time frame of more than 100microseconds is shown. Again, as shown in FIG. 8b, the frequency orspectral characteristics of the swept analog waveform is continuous overthe wide frequency range and, thus, the power is spread out over allfrequencies. As mentioned briefly above, from the standpoint of patientresponse variability, such waveform characteristics are preferable formicrocurrent stimulation therapy, and in particular, maculardegeneration therapy.

Referring now to FIGS. 4a-4 d, a method for treating visual systemdiseases, and in particular, a method for treating macular degenerationwill be described. Specifically, to treat macular degeneration, amicrocurrent stimulation therapy device, using a swept digital or pulsedsignal, similar to the embodiments described above, is used. Asmentioned above, in order to create a closed circuit for themicrocurrent stimulation device, a brass cylinder or rod preferably isheld in one hand of the patient, and a brass microcurrent stimulationprobe with a shielded handle is applied to the patient by the therapist.The brass cylinder or rod conducts the electric current allowing thecurrent to pass through the particular body part for therapy.

In accordance with one embodiment of the present invention, each eyethat shows signs of macular degeneration is treated by providing amicrocurrent through four points on the upper and four points on thelower eyelid for a total of eight points around the eye. FIG. 4aillustrates the eight points around the eye which are stimulated and thepreferred order of stimulation. For example, the stimulation preferablyoccurs in the order from point one to point eight. When stimulating theeyelid, the patient preferably looks away from the probe with eyesclosed. This rolls the macula closer to the stimulation point, keepingthe microcurrent from passing through dense eye structures, such aslens, iris and ciliany body, resulting in better microcurrentpenetration into the macula region. The eight points around the eye arestimulated using a current between about 50 to about 350 microamps, andmore preferably between about 150 and 250 microamps. In accordance withone preferred embodiment of the present invention, the current appliedto the eyelid is brought up until the patient sees light flashes and/orfeels the tinge of electricity. The current is then decreased so thatthe patient feels no discomfort. This is the preferred current levelused for the therapy.

In accordance with a preferred embodiment of the present invention, eachpoint around the eye is stimulated for about 8 to about 60 seconds, andmore preferably for about 30 seconds, using a sweep wave signal. Asdiscussed above, the sweep wave signal may comprise one swept signal, ortwo independent sweep wave signals combined by an adder/buffer circuit.In accordance with this aspect of the present invention, one of thesweep wave signals preferably comprises a rectangular sweep wave signalhaving a peak-to-peak voltage of between about 10 to about 30 volts, andmore preferably about 20 volts. In addition, the square or rectangularsweep wave signal preferably has a sweep wave frequency range of about 0to about 400 Hz, and more preferably of about 0 to about 35 Hz; has asweep time of between about 7 and about 60 seconds, and more preferablyof about 15 seconds; and has a duty cycle of between about 20 and about95 percent, and more preferably of about 75 percent. The other signalgenerator preferably provides a sweep wave signal having a lowerpeak-to-peak voltage than the first sweep wave signal. For example, thesecond sweep wave signal preferably has a peak-to-peak voltage ofbetween about 0.1 to about 4 volts and more preferably about 1 volt, ifneeded. In addition, the second sweep wave signal preferably has a sweepwave frequency range of about 500 to about 2 MHz, and more preferably ofabout 500 to about 1.5 MHz; and a sweep time of between about 7 andabout 60 seconds, and more preferably of about 15 seconds. The secondsweep wave signal may comprise a sinusoidal waveform, a square waveform,a triangular waveform, a ramp waveform, a step waveform, or the like.

In accordance with another preferred embodiment of the presentinvention, the second signal comprises a non-swept or fixed frequencysignal, rather than a swept or sweep wave signal. In accordance withthis aspect of the invention, the non-swept wave signal may comprise asinusoidal wave, a square or rectangular wave, a ramp wave, a step wave,or the like. Preferably, the non-swept wave signal has a peak orpeak-to-peak voltage of between about 0.1 to about 4 volts, and morepreferably about 1 volt. In addition, the fixed frequency of thenon-swept wave signal preferably is in the range of about 500 Hz to 2MHz, and more preferably in the range of about 500 Hz to 1.5 MHz.

In addition to stimulating points around the eye, the method fortreating macular degeneration may include treating other acupuncture orpressure points on the body. For example, as shown in FIG. 4a, there are2 points, A and B, on the forehead which can be used for microcurrentstimulation. In accordance with this aspect of the present invention,two probes preferably are attached to the frontal area of the foreheadat points A and B, and a microcurrcnt scan is applied to these pointsfor about 10 to 20 minutes, and more preferably for about 15 minutes. Inthis manner, a relaxation mode of the therapy procedure is applied tothe patient. That is, by attaching the electrodes to the forehead of thepatient and applying a microcurrent to that location, the conductance ofelectricity in the head area is increased, thus helping relax thepatient, as well as providing other therapeutic affects. For example, inthis relaxation mode, some of the microcurrent is scattered toward theeye region, thus supplying additional microcurrent therapy to the eyes.

In addition, as illustrated in FIG. 4b, there are eight acupuncture orpressure points on the back of the neck which may be stimulated duringmacular degeneration therapy. In accordance with this aspect of theinvention, each pressure point 1-8 is stimulated in ascending order forabout 20 to about 60 seconds. Similarly, FIG. 4c shows 10 acupuncture orpressure points on the ear which also may be stimulated for maculardegeneration therapy. As with the points around the eye and on the backof the neck, each point 1-10 on the ear is stimulated in ascending orderfor about 10 to about 30 seconds. Finally, FIG. 4d illustrates fourpressure points on an arm which also may be stimulated in the samemanner as with the eyes, neck and ears. In accordance with a preferredembodiment of the present invention, similar waveforms are used on theeyes, neck, ears and arms. However, in accordance with other preferredembodiments of the invention, different waveforms may be used on thedifferent body parts, depending on the therapeutic effect of aparticular waveform at a particular location.

In accordance with a preferred method for treating macular degeneration,patients initially are treated twice a day for 4 days and 3 times a weekthereafter.

With reference to FIG. 9, an embodiment which digitally controls themodulation frequency is shown in block diagram form. This embodimentincludes a controller 200, a read only memory (ROM) 204, adigital-to-analog converter (DAC) 208, a voltage controlled oscillator(VCO) 212, a voltage limiter circuit 214, a current level indicator 216,a data acquisition module 224, and a current sensor and limiter circuit228. These components allow digital frequency modulation (FM) of theoutput signal produced by the microcurrent stimulation therapy apparatus232. In other embodiments, an analog waveform generator could also beused in place of parts 200, 204 and 208.

The controller 200 reads values from a lookup table in the ROM 204 toproduce a digital word for the DAC 208. The DAC 208 converts a digitalword into an analog voltage which is then coupled to the VCO 212. Theanalog voltage frequency modulates the oscillation of the VCO 212 toproduce a modulated frequency. To modify the level of the signal undercontrol from the user, the modulated output from the VCO 212 passesthrough the voltage limiter circuit 214. The voltage control may beprovided by a potentiometer, or other known method.

Monitoring and regulating of the current applied to the patient isperformed with a current sensor and limiter circuit 228. The currentsensor and limiter circuit 228 regulates the signal to a level selectedby the user by using a potentiometer, or the like which is coupled tothe current control input. Additionally, the current sensor and limitercircuit 228 passes the signal through a resister so that the current canbe sensed as it varies the voltage drop across the resister. To allowapplication to a patient, the output from the current sensor and limitercircuit 228 is coupled to a probe tip. In this way, the controller candigitally modulate a signal frequency applied to the patient.

The current level indicator 216 displays the current level sensed fromthe signal and feeds this information to the data acquisition module224. The indicator 216 can have both visual and audio outputs. Forexample, it may be a series of LEDs which light up in successionaccording to the current level. Furthermore, the current level indicator216 can utilize digital and analog techniques to show the patient thepresent current applied.

The current measured by the current level indicator 216 is passed to thedata acquisition module 224. Additionally, the data acquisition module224 can record the applied voltage over time so that both current andvoltage is known. The physician can download the information from thedata acquisition module 224 to analyze the output signal applied to thepatient. In other embodiments, the current information could be fed backto the controller such that closed loop feedback could more preciselyadjust the output current.

The lookup table within the ROM 204 can store any number of frequencysequences. Additionally, the controller can repeat the entries of thelookup table in a loop to conserve room. Each digital word read from theROM 204 corresponds to an analog voltage. The analog voltage is appliedto the VCO 212 to produce a predetermined modulation frequency. The ROM204 is preferably a non-volatile and reprogrammable memory device suchas an EPROM, an EEPROM, a FLASH memory, or the like. Depending upon thetreatment regiment specified, the lookup table within the ROM can bemodified by the patient's physician. In this way, any number offrequency sequences can be produced by the therapy apparatus 232.

The digital modulation of the microcurrent stimulation therapy apparatus232 can provide precision in controlling the spectral response of thesignal applied to the patient. Over time, the spectral response exhibitsspecific frequency components which corresponded to the variousfrequencies produced by the VCO 212. As described above, the frequencyproduced by the VCO 212 is achieved from a digital data word stored in alookup table in the ROM 204. In a non-linear manner, the frequencycomponents from the lookup table could be distributed over the spectrum.The lookup table could sweep the frequency through the spectrum orachieve any different frequency at any time. Therapies for differenttypes of medical conditions my require a more complex spectral responsethan merely sweeping the frequency from one end of the spectrum to theother. The digital frequency modulation technique could, for example,sweep from 2 KHz through 4 KHz and then sweep from 7 KHz to 9 KHz. Toconserve space in the ROM 204, the controller 200 could repeat thedelivery of digital data words in a loop to continually repeat thefrequency modulation sequence. The wide variety of possible spectralresponses allows the therapy apparatus 232 to provide a response that isuseful in the treatment of many different health problems such asdiseases of the visual system (including macular degeneration andretinitis pigmentosa), orthopedic problems (including sciatica), painand fatigue disorders (including myofascial pain syndrome, fibromyalgia,sciatica, and neuralgia), and perhaps certain types of cancer (includingretinoblastoma cells).

The microcurrent stimulation therapy apparatus 232 can achieve smallelectronically controlled frequency variations where the change infrequency over time is automatic. This provides the capability to treata patient with a wider range of frequencies and frequency combinations.As mention above, the waveforms could be unipolar, bipolar or bi-phasic.Unipolar waveforms are characterized by being always positive or alwaysnegative; bipolar waveforms are characterized by being both positive andnegative, but not necessarily symmetric about the zero potential axis;and bi-phasic waveforms are characterized by being symmetric about thezero potential axis.

This embodiment utilizes frequency modulation (FM), to provide afrequency swept output waveform which distributes the specific frequencycomponents over time. Other embodiments with analog swept sinusoidaloutput signals which distribute the frequency over time produce acontinuous spectral density function. However, in the case of sweptdigital or pulse waveforms, the spectral density function will alsoexhibit specific frequency components distributed over time.Accordingly, the spectral density function may also exhibit discreteproperties. Digital frequency sweep techniques include (but are notlimited to) voltage/current control of an oscillator, programmablefrequency division of a oscillating signal and table look-up of thefrequency. For example, a programmable number of flip flops could dividea source frequency into any number of lower frequencies. Unlike priorart electro therapeutic systems that require manual frequency changes orsmall electronically controlled frequency variations, the change infrequency of this embodiment over time is automatic, providing thecapability to treat the patient with a wider range of frequencies andfrequency combinations.

With reference to FIG. 10, a microcurrent stimulation therapy apparatus332, which directly synthesizes the output waveform without using theabove described digital modulation technique, is shown in block diagramform. Direct synthesis is the process by which a waveform is recreatedby a controller 200 using values from a ROM 204 to control a signalsource 336. In the embodiment depicted in FIG. 9, a VCO would not berequired and the signal source 208 feeds directly to the current sensorand limiter 228. In this embodiment, the ROM 204 contains a look-uptable providing an output to the controller 200 that controls thevoltage level of the output signal from the signal source 208. Thedigital words are reformatted, if necessary, and coupled to the signalsource 336. The signal source 208 creates a voltage which corresponds tothe digital word.

In essence, the signal source 208 functions as a digital to analogconverter in this embodiment. The waveform output from the signal source208 is comprised of constituent voltage levels which over time create asignal of a single frequency or multiple frequencies. Each constituentvoltage corresponds to a digital word from the ROM 204. By using thisdirect digital synthesis technique, the signal could have any number ofpredetermined shapes. As can be appreciated by those skilled in the art,use direct digital synthesis allows producing complex waveforms withmany constituent frequency components.

To conserve storage space in the ROM 204, only the waveform for a singleperiod need be stored. The controller 200, being aware of the periodicnature of the waveform, could feed the period of the waveform in acontinuous loop to recreate the periodic nature of the waveform. Asimple example of this is a period which is comprised of a data word ofall zeros and a data word of all ones. When fed to the DAC 208 in aloop, the data words would create an oscillating square wave with aperiod of twice the sampling period of the signal source 336. In thisway, waveforms of any shape can be directly digitally synthesized.

Other variations of the circuit in FIG. 10 are also possible. In anotherembodiment, the controller 200 reads a value from the ROM 204 to producea voltage. The voltage is coupled to the signal source 336 where thevoltage is used to select a oscillation frequency. As the voltagevaries, so does the oscillation frequency, such that a range offrequencies is possible as proscribed by the ROM 204. In thisembodiment, the signal source 336 performs as a voltage controlledoscillator where the voltage which corresponds to the digital wordselects the output frequency. However, it is noted a current could alsobe used to control the signal source 336.

In yet another embodiment, the controller 200 reads a value from the ROM204 which corresponds to a pulse. The pulse is created by the controller200 and fed to the signal source 336. The signal source uses the pulseto select a frequency to generate. By varying the pulse, any number offrequencies are selected.

With reference to FIGS. 11 and 12, embodiments of a triangular waveformand a ramp waveform are respectively shown. Voltage is shown in theordinate direction and time is shown along the abscissa.

Referring next to FIGS. 13A and 13B, embodiments of bi-phasic pulses areshown. More specifically, FIG. 13A shows a bipolar return-to-zero pulsewaveform, and FIG. 13B shows a Manchester code pulse waveform. Voltageis shown in the ordinate direction and time is shown along the abscissa.Bi-phasic pulse waveforms have pulses that have a positive and negativepolarity and arc not necessarily symmetrical with respect to positiveand negative polarity.

In conclusion, the present invention provides novel methods andapparatus for using microcurrent stimulation therapy to treat variousphysiological problems, such as pain, wounds and visual eye diseases.While a detailed description of presently preferred embodiments of theinvention have been given above, various alternatives, modifications,and equivalents will be apparent to those skilled in the art. Forexample, while a particular circuit configuration is given for a sweepwave signal generator of the present invention, various other circuitconfigurations may be used; such as, digital signal processing circuitsor digitally generated wave signal circuits. In addition, while onepreferred method for treating macular degeneration is disclosed, othersuitable methods may be used to treat macular degeneration, other eyediseases or other chronic problems such as pain and persistent sores.Thus, any number of sweep signal generator circuits and therapy methodsmay be used without varying from the spirit of the invention. Therefore,the above description should not be taken as limiting the scope of theinvention which is defined by the appended claims.

What is claimed is:
 1. A method for providing microcurrent stimulationtherapy to a body part, comprising the steps of: receiving a firstdigital data word; producing a first frequency related to the firstdigital data word; applying a first microcurrent signal at the firstfrequency to the body part; receiving a second digital data word;producing a second frequency related to the second digital data word;applying a second microcurrent signal at the second frequency to thebody part proximate an eye, and limiting a current level of the firstand second microcurrent signals applied to the body part.
 2. The methodas recited in claim 1, wherein the stimulation therapy comprises therapyfor treating visual system diseases, and the applying steps includeapplying the microcurrent signal to an eyelid proximate an eye having avisual system disease.
 3. The method as recited in claim 1, wherein thetherapy treats at least one of macular degeneration, retinitispigmentosa, sciatica, pain disorders, fatigue disorders, myofascial painsyndrome, fibromyalgia, neuralgia, and cancer.
 4. The method as recitedin claim 1, wherein the first microcurrent signal comprises a waveformselected from a group of waveforms comprising a sine wave, a squarewave, a triangular wave, a ramp wave, a step wave, an unipolar wave, abipolar wave, and a bi-phasic wave.
 5. The method as recited in claim 1,further comprising the step of limiting a voltage level of the first andsecond microcurrent signals applied to the body part.
 6. The method asrecited in claim 1, wherein a current level is in the range of about 50microamps to about 200 microamps.
 7. A method for providing microcurrentstimulation therapy to a body part, comprising the steps of: receiving afirst digital data word; producing a first analog voltage related to thefirst digital data word; applying the first analog voltage to the bodypart; inducing a first microcurrent to flow with the first analogvoltage; receiving a second digital data word; producing a second analogvoltage related to the second digital data word; applying the secondanalog voltage to the body part proximate an eye having an affliction,wherein the first analog voltage is different from the second analogvoltage; and inducing a second microcurrent to flow with the secondanalog voltage.
 8. The method as recited in claim 7, wherein the therapytreats at least one of macular degeneration, retinitis pigmentosa,sciatica, pain disorders, fatigue disorders, myofascial pain syndrome,fibromyalgia, neuralgia, and cancer.
 9. The method as recited in claim7, further comprising the step of producing a periodic waveform whichincludes the first and second analog voltages, wherein the periodicwaveform is selected from the group of waveforms comprising sine wave,square wave, triangular wave, ramp wave, step wave, unipolar wave,bipolar wave, and bi-phasic wave.
 10. The method as recited in claim 7,further comprising the step of limiting a current level of the first andsecond analog voltages applied to the body part.
 11. The method asrecited in claim 7, further including the step of repeating the forgoingsteps a plurality of times to produce a periodic waveform.
 12. Anapparatus for supplying an electrical signal to a body part in order toprovide microcurrent stimulation therapy to the body part, comprising: adigital-to-analog converter; a controller coupled to thedigital-to-analog converter; a current limiter coupled to the electricalsignal; and a plurality of digital data words, wherein the controllercouples the digital data words to the digital-to-analog converter inorder to generate the electrical signal.
 13. The apparatus as recited inclaim 12, further comprising a voltage controlled oscillator, wherein:the digital-to-analog converter produces an analog voltage which iscoupled to the voltage controlled oscillator; and the analog voltagerelates to an output frequency of the voltage controlled oscillator. 14.The apparatus as recited in claim 12, wherein a look-up table includesthe plurality of digital data words.
 15. The apparatus as recited inclaim 12, wherein the digital data words are stored in a reprogrammableand non-volatile memory.
 16. The apparatus as recited in claim 12,wherein the digital-to-analog converter produces a plurality of voltageswhich form a periodic waveform.
 17. The apparatus as recited in claim12, further comprising a current limiting circuit coupled to thedigital-to-analog converter.
 18. The apparatus as recited in claim 12,further comprising a current level indicator which conveys the currentlevel of the electrical signal.
 19. The apparatus as recited in claim12, further comprising a current measuring device adapted to measure thecurrent level of the electrical signal.
 20. The apparatus as recited inclaim 12, further comprising a data acquisition module for collectingcurrent and voltage level information.
 21. A method for providingmicrocurrent stimulation signals capable of providing therapy to a bodypart, comprising the steps of: receiving a first digital data word;producing a first microcurrent signal related to the first data word;receiving a second digital data word; producing a second microcurrentsignal related to the second data word; and treating at least one ofmacular degeneration, retinitis pigmentosa, sciatica, fatigue disorders,myofascial pain syndrome, fibromyalgia, neuralgia, and cancer.
 22. Amethod for providing microcurrent stimulation signals capable ofproviding therapy to a body part, comprising the steps of: receiving adata word; producing a microcurrent signal related to the data word; andapplying the microcurrent signal to a point proximate to an eye having avisual system disease.
 23. A method for providing microcurrentstimulation signals capable of providing therapy to a body part,comprising the steps of: receiving a data word; producing a microcurrentsignal related to the data word; and treating at least one of maculardegeneration, retinitis pigmentosa, sciatica, fatigue disorders,myofascial pain syndrome, fibromyalgia, neuralgia, and cancer.